Free diving apparatus



L mm W. B. M LEAN mm zzz FREE DIVING APPARATUS Filed Nov. 10, 1954 55/575 5 Ami; i

4 INVENTOR.

WlLLlAM B. MC LEAN KMWQM'M ATi'oRYs United States Patent FREE DIVINGAPPARATUS William B. McLean, China Lake, (Ialii.

Application November 10, 1954, Serial No. sear/s 7 Claims. (Ql.128--142) (Granted Title 35, U. S. Code (1952), see. 266) The inventiondescribed herein may be manufactured and used by or for the Governmentof the United States of America for governmental purposes without thepayment of any royalties thereon or therefor.

This invention relates to apparatus for providing breathable air at thecorrect pressure to an under water diver, and in particular to freediving apparatus in which the supply of breathable air is carried by thediver rather than supplied to him from the surface.

It is an object of this invention to provide improved free divingapparatus.

it is a further object or" this invention to provide free divingapparatus in which the volume of all the parts filled with breathablegas at breathing pressure is substantially less than the normal capacityof the lungs of the average human so that a separate conduit for exhaledgas is not required.

It is a still further object of this invention to provide free divingapparatus in which all water in the breathing system will collect byaction of gravity at the exhalation valve, when the diver is in thenormal swimming position, so that such water can be expelled when thediver exhales.

It is a still further object of this invention to provide free divingapparatus in which the pressure regulating valve is normally held in theclosed position solely by the action of high pressure air in the supplyline so that the pressure required to open the valve is reduced as thepressure in the storage tank reduces, thus permitting uniform breathingwithout the need of an auxiliary pressure reducing valve.

it is still another object of this invention to provide free divingapparatus in which the parts of the system which normally contain air atbreathing pressure may be filled with water when not in use and whichprevents the escape of air at such times.

It is a still further object of this invention to provide free divingapparatus which subjects the diver to minimum pressure differentials atthose parts of his body most sensitive to pressure differentials.

Other objects and many of the attendants advantages of this inventionwill be readily appreciated as the same become better understood byreference to the following detailed description when considered inconnection with the accompanying drawing wherein:

Fig. l is a section taken on line 1-1 of Fig. 2 with part of theinvention shown in elevation, p

Fig. 2 is a section taken on line 22 of Fig. 1,

Fig. 3 is a side elevation of a diver wearing the free diving apparatus,

Fig. 4 is a section through the high pressure line, and

Fig. 5 is an enlarged sectional view of details of the pressureregulating valve.

In Fig. 1 and 2 the portions of the free diving apparatus which aretilled with breathable gas at breathable pressure, or the low pressureunit, areillustrated. Hollow cylindrical member, or case, has secured toit cover 2,743,722 Patented May 1,

12. In the example illustrated cover 12 is secured to case 10 by aplurality of screws 14. Case 10 and cover 12 can be made from anysuitable material such as Bake lite, stainless steel, e tc. Flexiblediaphragm 16, which in a preferred form is made of a suitable plastic,is mounted between case 10 and cover 12. The interior of case 10 and theinner wall of diaphragm 16 form low pressure chamber 18. Opening 24 isformed in cover 12 so that water at the ambient pressure of the sea mayen gage the outer wall of diaphragm 16. Pressure regulating valve 22 ismounted in case 10. Valve 22 consists of valve casing 24 in which isformed valve seat 26, and valve body member 23. Valve casing 24 isrnade, in a preferred form, of brass, and member 28 is made of asuitable material such as nylon or teflon. Valve body member 28, seeFig. 5, is provided with a stem 30 which extends beyond valve casing 24and into chamber 13 when member 28 is seated against valve seat 26 toshut valve 22. Casing 24 is secured in case it) by nut 32 which isthreadedly secured on casing 24.. High pressure hose 34 is fixedlysecured to casing 24 of pressure regulating valve 22. Lever arm 36,which is illustrated as being ring shaped as seen in Fig. 2 is pivotallymounted on valve casing 24 by screws 38. Lever arm 36 is "mounted so asto engage the end of stem Bit of valve body member 28 when lever arm 36is moved away from cover 12 pivoting at screw 33 to open valve 22.

Exhalation, or exhaust, valve 40 comprises guard member a2 and flexiblediaphragm 44- which is secured to case in by bolt 46 and nut 4-8.Diaphragm 44 is mounted so as to cover a plurality of openings 50 formedin casing 10. Guard 42 is spaced a short distance away from diaphragm 44so that diaphragm 44 may move to uncover openings 50 to permit thecontents of chamber 18 to escape, or to be vented, when the pressurewithin chamber 18 is greater than the ambient pressure of thesurrounding water.

Central opening 52 is formed in case 10. Flexible air hose 54 has oneend secured about the means forming opening 52. Mouthpiece 56 is mountedat the other end of flexible air hose 54 and is adapted to be held inthe mouth of the diver.

Referring now to Fig. 3, tank 53 which contains a supply of breathablegas under high pressure, i. e., for example 2000 pounds per square inch,is mounted on the back of the diver by means of a conventional har nesswhich is not illustrated. Tank 58 has a valve 60 which is open when thediver desires to receive air from the tank. High pressure line 34 runsfrom the outlet of valve 60 to regulating valve 22. The pressure of thegas within line 34 is substantially that which exists Within tank 58 andno intermediate pressure reducing valve is used or necessary. Highpressure line 3d is provided with a restricted opening 62, as seen in 4,which limits the maximum rate of how of gas into line 34. As a result ifline 34 is broken or disconnected from pressure regulating valve 22 inany manner, the free end of line 34 will not whip about in the water andpossibly injure the diver.

When the diver inhales, the pressure within chamber 18 decreases belowthat of the ambient pressure of the water. Diaphragm It? moves away fromcover 1 2. and into chamber 18 as a result of the pressure differential.The movement of diaphragm 16 causes lever arm 36 to press stem 30 inwardto move valve body 23 away from valve seat 26. The diameters of valvebody 28 and stem 30 are such that air can flow around body 23 and stem30 when body 28 is moved away from sealing engagement with valve seat26. This opens valve 22 and perm'its air-frombigh pressure line 34 toenter into chamber 18. Valve casing 24 has grooves 64 formed on therounded surface 66 about opening 68 so that the lever arm 36 cannot sealopening 68 and prevent air from entering chamber 18.

As the diver inhales, the breathable air enters the chamber 18 and isdrawn through breathing hose 54 into his mouth through mouthpiece 56 andthence into his lungs. During inhalation the decreased pressure withinchamber 18 causes diaphragm 44 to seal openings 50 of exhalation valveand thus prevent water from entering into chamber 18 through theopenings 50. At the termination of inhalation, the pressure differentialbetween the air in chamber 18 and that of the pressure of the wateracting on diaphragm 16 decreases. The action of the high pressure airagainst valve body member 28 causes the valve body member to seatagainst valve seat 26 to close valve 22 and move lever arm as outwardly.At this time the diaphragm r6 ofiers no resistance to the movement oflever arm 36.

When the diver exhales, the exhaled air passes from his lungs throughmouthpiece 56, hose 54 into chamber 18. During exhalation the pressurewithin chamber 1? is increased so that it is greater than the ambientpressure of the sea. Diaphragm 44 is forced by the pressure away fromopenings and the exhaled air is vented into the sea.

As seen in Fig. 3, case 10 is mounted high on the chest of the diver.There is a twofold reason for this location of case 10. The portion ofthe diver which is most sensitive to pressure differential is the lipsand mouth rather than the lungs since the walls of the lungs arereinforced by the ribs while the lips and cheeks are unsupported by bonestructure. By mounting case 10 as close to the mouth of the diver as ispossible, the difference between the pressure of the sea and thepressure within chamber 13 acting on diaphragm 16 is normally only a fewinches of water at the most and thus the pressure exerted against thelips and mouth of the diver are so small as to not be uncomfortable.Locating case 10 close to the divers mouth also reduces the length offlexible breathing hose 54 required, and as a result, the volume ofchamber 18 and hose 54 is minimized. The volume of chamber 18 and hose54, in a preferred example, is 4 fluid ounces, which is less than 0 the64 fluid ounces which is the lung capacity of the average human. As aresult only a small portion of the exhaled air remains in chamber 18 andhose 54 and is rebreathed when the diver inhales.

Exhalation valve 40 is mounted when the diver is in the normal swimmingposition, so that it is at the lowest point of chamber 18. Thus anywater that may be admitted into chamber 18 will collect near valve 40and will be vented into the sea when the diver exhales. Pressureregulating valve 22 is mounted beside exhalation valve 40 as seen inFig. 2. Even if chamber 18 is full of water when the diver inhales, thehigh pressure air from valve 22 blows the water away from opening 52 sothat the diver will be able to breathe air rather than inhale water.

The diver may desire to leave the free diving apparatus at the bottom ofthe sea while he swims about on the surface, or leave the mouthpiece outof his month while swimming on the surface. When the diver removesmouthpiece 56 from his mouth, hose 54 and chamber 18 will fill withwater. However, no air will enter chamber 18 through regulating valve 22since the pressure within the chamber will equal that of the sea actingagainst diaphragm 16 and thus there will be no pressure differential toopen valve 22, which is normally biased closed by the action of the highpressure air in line 34 It is, therefore, not necessary to shut valve 60of tank 58 under these conditions. When the diver wishes to again usethe free diving apparatus, he exhales into the mouthpiece 56. A smallportion of the air within his lungs is sufiicient to eliminate waterwithin hose 54 and chamher 18 since their total volume is less than 0the normal volume of the divers lungs.

Obviously many modifications and variations of the present invention arepossible in the light of the above teachings. It is, therefore, to beunderstood that within the scope of the appended claims the inventionmay be practiced otherwise than as specifically described.

What is claimed is:

1. Free diving apparatus for an under water diver comprising a chamber,valve means for admitting high pressure gas into said chamber when thepressure within the chamber is less than the ambient pressure of thewater, conduit means for conducting high pressure breathable gas from asource of said valve means, and means associated with the chamber forpermitting the contents of the chamber to escape when the pressurewithin the chamber is greater than the ambient pressure of the water,and means for communicating the interior of the chamber with the lungsof the diver, the combined volume of the chamber and communicating meansbeing substantially less than the normal lung capacity of the averagehuman.

2. Free diving apparatus for an under water diver comprising a chamber,valve means for admitting high pressure gas into said chamber when thepressure within the chamber is less than the ambient pressure of thewater, conduit means for conducting high pressure breathable gas from asource to said valve means, means associated with the chamber forpermitting the contents of the chamber to escape when the pressurewithin the chamber is greater than the ambient pressure of the water,and

means for communicating the interior of the chamber with the lungs ofthe diver, the volume of the chamber and communicating means beingsubstantially equal to 4 the normal lung capacity of the average human.

3. Free diving apparatus for an under water diver comprising a source ofpressurized breathable gas, a chamber, a conduit, a pressure regulatingvalve, said conduit conducting breathable gas from said source to saidregulating valve, said pressure regulating valve admitting gas from saidsource into said chamber when the pressure Within the chamber is lessthan the ambient pressure of the water, exhaust valve means for ventingthe chamber when the pressure within the chamber is greater than theambient pressure of the water, and means for communicating the interiorof the chamber with the lungs of the diver, the volume of the chamberand communicating means being substantially A the normal lung capacityof the average human.

4. Free diving apparatus for an under water diver comprising meansforming a chamber, a pressure regulating valve mounted in the chamber, ahigh pressure line adapted to conduct high pressure breathable gas froma source to the pressure regulating valve, said pressure regulatingvalve opening when the pressure within the chamber is less than theambient pressure of the water to admit breathable gas into said chamber,an exhalation valve mounted in the means forming the chamber forallowing the contents of the chamber to escape when the pressure withinthe chamber exceeds the ambient pressure of the water, and a flexiblehose having a mouthpiece in communication with said chamber, themouthpiece of said hose adapted to be held in the mouth of the diver,the volume of the hose and chamber being substantially the volume of thedivers lung capacity.

5. Free under water diving apparatus comprising a source of pressurizedbreathable gas, means forming a chamber, a portion of said means forminga chamber comprising a flexible wall portion exposed on its outer sideto the ambient pressure of the Water surrounding the apparatus, apressure regulating valve mounted in said means forming a chamber, ahigh pressure conduit extending from the source of breathable gas to thepressure regulating valve, said pressure regulating valve admittingbreathable gas into the chamber when the pressure within the chamber isless than the ambient pressure of the water an exhalation valve forventing the chamber when the pressure within the chamber is above theambient pres sure, and a flexible hose having a mouthpiece incommunication with the chamber, the volume of the hose and chamber beingsubstantially 5 the normal lung capacity of the diver.

6. Free diving apparatus for an under water diver comprising a hollowcase, a cover for said case, a flexible diaphragm secured between saidcase and said cover, the interior of the case and one wall of saiddiaphragm forming a chamber, an opening in said cover so that the otherwall of said diaphragm is exposed to the ambient pressure of the water,a high pressure line, a pressure regulating valve mounted in said case,said high pressure line having one end attached to and adapted toconduct high pressure breathable gas to the pressure regulating valvefrom a suitable source, a lever pivotally mounted on said valve mountedwithin said chamber, said lever arm adapted to be moved by saiddiaphragm when the pressure within the chamber is less than the ambientpressure of the water to open said valve and admit breathable gas intosaid chamber, an exhalation valve mounted in said case at the lowestposition of said chamber when the diver using the apparatus is in thenormal swimming position, said exhalation valve comprising a pluralityof openings through the case communicating said chamber with the Watersurrounding said case, a flexible diaphragm mounted on the exterior ofsaid case for closing said exhalation valve openings when the pressurewithin the chamber is less than the ambient pressure of the water, and aprotective cover for said exhalation valve diaphragm mount-ed on saidcase over said diaphragm and slightly spaced therefrom so that saiddiaphragm is between said case and said protective cover, said pressureregulating valve being mounted closely adjacent said exhalation valve, aflexible breathing hose having one end thereof mounted on said case sothat said breathing hose is in communication with said chamber, and amouthpiece at the other end of said flexible breathing hose.

7. Free diving apparatus for an under water diver comprising a hollowcase, a cover for said case, a flexible diaphragm secured between saidcase and said cover, the interior of the case and one wall of saiddiaphragm forming a chamber, at least one opening in said cover so thatthe other wall of said diaphragm is exposed to the ambient pressure ofthe water, a high pressure line having a re stricted passage forlimiting the rate of gas flow therethrough, a pressure regulating valvemounted in said case, said high pressure line having one end attached toand adapted to conduct high pressure breathable gas to the pressureregulating valve from a suitable source, a lever arm pivotally mountedon said valve mounted within said chamber, said lever arm adapted to bemoved by said diaphragm when the pressure within the chamber is lessthan the ambient pressure of the water to open said valve and admitbreathable gas into said chamber, an exhalation valve mounted in saidcase at the lowest position of said chamber when the diver using theapparatus is in the normal swimming position, said exhalation valvecomprising a plurality of openings through the case com municating saidchamber with the Water surrounding said case, a flexible diaphragmmounted on the exterior of said case for closing said openings when thepressure within the chamber is less than the ambient pressure of thewater, and a protective cover for said exhalation valve diaphragmmounted on said case over said diaphragm and slightly spaced therefromso that said diaphragm is between said case and said protective cover,a. flexible breathing hose having one end thereof mounted on said caseso that said breathing hose is in communication with said chamber, and amouthpiece at the other end of said flexible breathing hose.

References Cited in the file of this patent UNITED STATES PATENTS2,682,871 Arpin July 6, 1954 2,695,609 Nourse et al Nov. 30, 1954FOREIGN PATENTS 129,382 Australia Oct. 11, 1948 284,946 Switzerland Ian.5, 1953

